The hard truth first: if you drink protein shakes, your habit is getting more expensive faster than almost anything else on the supermarket shelf, and there is no sign of the line bending back down yet.
The BBC followed the price of a 4.5kg bag of whey through the eyes of one London buyer, Amarpreet Singh. It cost around £60 in 2020. Last year it reached £120, and he eventually found one on eBay for £90. The same bag now sells for £170. Among his gym friends the squeeze has a nickname: “proteinflation”.
The numbers behind the nickname come from a handful of places at once. Protein powders and shakes spent years as a bodybuilder niche and have since gone mainstream, with manufacturers adding high-protein versions to everything from bagels to water, the BBC reports. Demand built while supply stayed tight. The raw ingredient, whey, is a by-product of cheese-making, so its availability tracks dairy economics rather than gym culture.
Dairy itself had a punishing summer. Researchers told the Energy and Climate Intelligence Unit that extreme heat cost British farmers the equivalent of 240 million litres of milk deliveries between May and August, a shock that feeds straight into whey supply and pricing.
Then there is the GLP-1 effect. Weight-loss drugs such as Wegovy and Mounjaro have pulled a new cohort of users towards high-protein diets to hold onto muscle while they lose weight, adding demand that nobody forecast when the category was still mostly teenagers and bodybuilders.
Buyers are adapting the way people always do when a staple outruns them. A 19-year-old student interviewed by the BBC said she rations her 420g tub and uses less than the label suggests. A 32-year-old from Manchester put his monthly spend up from around £45 a year ago to £60 now, and said he simply absorbed it.
The honest summary for anyone budgeting: the category has shifted from discretionary to structural in millions of shopping baskets, and structural categories rarely re-price downwards unless supply loosens or demand cools. Neither has happened yet.